According to the vital statistics made by the Japanese Ministry of Health, Labor and Welfare, the first-ranked of the causes of death of Japanese is cancer, the second-ranked is cardiopathy, and the third-ranked is cerebral apoplexy. Particularly, the number of people dying from cerebral apoplexy and the number of people suffering from sequelae of cerebral apoplexy have been increasing, and there is a pressing need to establish a cure for cerebral apoplexy.
In recent years, in the cure of cerebral apoplexy, a thrombolytic cure based on the use of thrombolytics for curing cerebral infarct in acute phase has been developed and producing therapeutic effects, but a limitation of this cure is being pointed out. Specifically, it has been recognized from doctors' experiences that a long time may be taken for thrombolysis by a thrombolytic, a thrombus reduced in size may fly further to form a new thrombosis site, or there may be thrombi which cannot be dissolved by thrombolytics.
In the case of cerebral infarct, it has been verified in USA and Europe that not only the probability of survival is increased but also the probability of sequelae is reduced if the bloodstream can be recovered in three hours after the sideration of infarct. Therefore, there is a keen demand for the development of a medical implement which can be inserted into a cerebral blood vessel and by which a thrombus in the cerebral blood vessel can be directly removed.
As one of such medical implements, there has been proposed a medical recovering basket having a basket (foreign matter catching section) which is movable from a retracted position to an expanded position in relation to a sheath (catheter) (refer to, for example, JP-A-2002-516139).
This medical implement, however, has the problem that in the case where the foreign matter (thrombus) is comparatively soft, for example, the foreign matter (thrombus) would leak out through gaps present in a spiral leg constituting the basket, making it difficult to satisfactorily catch the foreign matter (thrombus).